Exporting an Excel plot as SVG or PNG

Copy it as a plot into powerpoint. Save in powerpoint as a emf. Open the emf in e.g. inkscape, then save as svg. Vectors are preserved.

2020 Update

This is now easily possible manually

Just right-click the chart and select "Save as Graphic" where you have the option to save as .svg.

Solution for VBA

Unfortunately, this relatively new feature is not yet supported by the object model. Chart.Export fileName:="MyChart", FilterName:="SVG" will result in an empty file as of now. Therefore, exporting with VBA is still very difficult and only possible by automating the "manual" method. I created a solution that is doing exactly that and tried to make it easy to implement in other code. For the full solution, check out this answer.

I think you have set yourself a very difficult task.

If you copy a plot area to the clipboard and look at the formats available with Application.ClipboardFormats, the only vector format offered is PICT. Perhaps this could be an avenue to investigate...

If you 'Print to PDF' you should be able to convert it to SVG-format. There's several converters online, I would use Adobe Illustrator though.